"Incorporating intermediate biomarkers of folate with colorectal cancer" The goal of this proposal is to measure intermediate biomarkers and to evaluate these with statistical methods designed to elucidate the underlying etiologic mechanism of colorectal cancer. The proposal leverages existing genetic data from studies conducted within the Colon Cancer Family Registry (Colon CFR), an NCI-supported consortium initiated in 1997 and dedicated to the establishment of a comprehensive collaborative infrastructure for interdisciplinary studies in the genetics and genetic epidemiology of colorectal cancer. The subjects include 1,531 controls genotyped in a candidate gene study of FOCM pathway genes (RO1CA112237), and 999 controls genotyped in a genome wide association study of colon CFR cases (U01CA122839). In these subjects, we will evaluate plasma measures within one carbon metabolism (plasma folate, vitamins B2, B6, B12, methionine, methyl malonic acid, creatinine, plasma total Hcy (tHcy), and DNA methylation in circulating lymphocytes (PBL)). In addition, we build upon our previous work in developing statistical methods for modeling genetic associations in putative disease pathways. These models integrate various levels of data, e.g. genotypes, gene expression, biomarkers, and exogenous exposures, with prior information to build more comprehensive statistical models for better prioritization, estimation, and characterization of genetic effects. PUBLIC HEALTH RELEVANCE: The overall goal of this proposal is to gain further insight into the underlying etiologic mechanism of colorectal cancer. We will accomplish this by first measuring intermediate biomarkers relevant to folate associated one- carbon metabolism in subjects with existing genotype data from a related candidate gene pathway-based and genome-wide association studies (GWAS). Then using novel statistical methods, we will investigate SNP- biomarker, SNP-disease, and pathway-disease associations to provide more insight into the complex effects of folate on the colorectal carcinogenic process.